It turns out that it was a Chrome extensions that was causing the problem, but I have no idea which one. I was doing some random cleanup earlier today and part of that was deleting some extensions I wasn’t using, and now Tweet Blender seems to be working fine in all versions of Chrome.
It was completely unrelated cleanup, but it makes sense that it was an extension causing the problem. Canary was the only one working and it doesn’t have many extensions installed, and the regular, beta and dev versions all had the same extensions, and none of them worked.
If I’m able to figure out which extension it was I’ll definitely let you know.
Thanks for all your help on this! I’m glad I stuck it out with Tweet Blender, it’s definitely still the best Twitter app out there.
PS – Kinda moot now, but this was all done using Windows.